Fourier Transform Infrared Research Articles

Molybdenum disulfide nanosheets hybridized with lysine molecules for highly efficient near-infrared photothermal energy conversion

Molybdenum disulfide nanosheets hybridized with lysine molecules for highly efficient near-infrared photothermal energy conversion

Immobilization of Trametes versicolor laccase on LDH/alginate composite beads for improved textile dyes decolorization.

Laccase is an oxido-reductase known for its applications in biomass valorization (lignin depolymerization), in fine chemicals (building-blocks synthesis) or in environment (wastewater treatment). It works with molecular oxygen and produces water as its only by-product. However, its practical use remains limited due to the low stability and poor reusability of free laccase. To overcome these challenges, laccase from Trametes versicolor was immobilized onto layered double hydroxide and alginate composite beads by a glutaraldehyde cross-linker to create an easily separable and stable enzyme. Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the as-synthesized composite beads (laccase@MgFe(LDH)/alginate). The activity of the immobilized laccase was measured with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) model substrate. Here, the optimal conditions of laccase immobilization were explored and the effects of various conditions of immobilization, pH, storage stability and thermal resistance of the (laccase@MgFe(LDH)/alginate) were also studied. The results revealed that the optimal conditions for laccase immobilization were a concentration of glutaraldehyde of 2.5%, an amount of laccase (0.5U/mg) of 2mg/mL, and an immobilization time of 6h. The stability of (laccase@MgFe(LDH)/alginate) was >70% of its initial activity, even after 10cycles. The study of dye decolorization showed up to 74% of methylene blue (MB) and 69% of Crystal violet (CV) degradation, suggesting the use of immobilized laccase on MgFe(LDH)/alginate composite beads as a promising and environmentally friendly tool for the degradation of environmental pollutants, in particular for the removal of textile dyes from wastewater.

Structural and thermal insights into the luminescent behavior of Dy³⁺-Doped BaZrO₃ with alkali metal codopants under UV radiation.

This study investigates the structural, thermal, and photoluminescent properties of Dy³⁺-doped BaZrO₃ (BZO) perovskites, synthesized via a co-precipitation method, incorporating alkali metal codopants (Li⁺, Na⁺, and K⁺). X-ray diffraction (XRD) analysis confirmed the retention of the cubic perovskite phase following doping, with Rietveld refinement further revealing minor lattice distortions due to Dy³⁺ incorporation. The Williamson-Hall (W-H) analysis revealed average crystallite sizes of 53nm and 66nm for undoped and 0.01 Dy³⁺-doped BaZrO₃, respectively, with corresponding micro-strain values of 1.79×10⁻³ and 1.81×10⁻³, suggesting lattice distortions due to incorporation of Dy³⁺. Fourier transform infrared (FTIR) spectroscopy confirmed the cubic perovskite structure and subtle structural modifications upon doping. Notably, the absence of moisture-related peaks highlights the effectiveness of the synthesis process, including rigorous drying and calcination steps that prevented hydrous species. Photoluminescence (PL) analysis of Dy³⁺-doped BaZrO₃ exhibited three prominent emission peaks at 452nm, 573nm, and 656nm under 368nm excitation. These peaks correspond to the characteristic intra-4f electronic transitions of Dy³⁺ ions, specifically, 4I13/2 to 6H15/2, 4F9/2 to 6H13/2, and 4F9/2 to 6H11/2, representing blue, yellow, and red emissions, respectively. Photoluminescence decay studies showed multi-exponential behavior, with the average lifetime decreasing from 641 μs in undoped BZO to 492 μs in Dy³⁺-doped samples attributed to enhanced non-radiative recombination pathways. Among the codopants, Li⁺ demonstrated the most significant improvement in luminescence intensity and thermal stability by mitigating defects and optimizing charge compensation.

The effect of glass container surface silanol density on monoclonal antibody formulation stability after application of mechanical shock.

This study investigates the effect of silanol density on the surface of glass containers on the stability of monoclonal antibody (mAb) formulations subjected to mechanical stress. By calcining Type I glass containers at different temperatures, we altered the concentration of silanols on the glass surface and examined its impact on the stability of protein formulations under mechanical stress. Contact angle measurements and Fourier Transform Infrared (FTIR) spectroscopy indicated that silanol formation influences the hydrophilicity of the surface. Additionally, mAb solutions filled in Type I glass containers with varying silanol densities were repeatedly dropped from a height of 0.5m to simulate mechanical stress during transport. The results demonstrated that increasing surface silanol density reduces protein monomer loss and the formation of protein aggregates and subvisible particles. Furthermore, protein aggregates and subvisible particles formed by dropping did not activate the complement in human serum in vitro. Adjusting the silanol density on the glass container surface offers an economical and environmentally friendly approach to improving the stability of mAb formulations during transportation.

Smart packaging films based on gelatin/κ-carrageenan integrated with gromwell root extract rich in shikonin and carbon dots for real-time monitoring of shrimp freshness.

Multifunctional pH-responsive gelatin/κ-carrageenan (GC) blend films containing gromwell (Lithospermum erythrorhizon [LE]) root ethanolic extract (LE-EE) rich in shikonin or shikonin rich extract (SRE) and carbon dots (LE carbon dots [LE-CDs]) were prepared and characterized. The hydrothermal method was adopted for the synthesis of LE-CDs, which displayed a blue color under UV light. The obtained LE-CDs possessed exceptional UV barrier, antioxidant and antimicrobial activities. The enhanced activities were recorded when the level of LE-CDs upsurged (p<0.05). Transmission electron microscopic (TEM) and Fourier transform infrared (FTIR) results revealed the typical morphology and chemical composition of LE-CDs. LE-CDs of 1 and 3% (w/w) were incorporated as the active fillers along with SRE into the GC blend film by the solvent casting method. Developed films showed a slight decrease in tensile and water vapor barrier properties with the inclusion of both additives. Color and opaqueness of the film became darker as the additives were incorporated, whereas the thermal property was greatly enhanced. Film containing 3% LE-CDs blocked UV-A and UV-B by 93.30 and 99.81%, respectively. GC/SRE/3%CD film exhibited strong radical scavenging and antibacterial activities against Listeria monocytogenes and Escherichia coli, in which the growth was terminated after 12h. Film had a pH-dependent color change, depending on various pH levels (2-12). Shrimp freshness could be monitored as indicated by the shift to bluish color after 48h. Therefore, this finding indicated that incorporating biomass-derived CDs and natural colorants into biopolymer films, especially GC blend films, could offer diverse strategies for maintaining safety and prolonging shelf life in response to the growing need for smart packaging for food applications.

Synthesis, single crystal investigations, DFT studies, biological activities, DNA cytotoxicity and molecular docking studies of copper(II) complex derived from the new o-vanillin Schiff base ligand

Synthesis, single crystal investigations, DFT studies, biological activities, DNA cytotoxicity and molecular docking studies of copper(II) complex derived from the new o-vanillin Schiff base ligand

Al3+ and H+ substitutions in TiO2 polymorphs: Structural and vibrational investigations

Abstract Rutile is the most common TiO2 mineral on Earth’s surface and transforms to CaCl2- and α-PbO2-type structures at elevated pressures in subducted basaltic crusts. In this study, we synthesized hydrous CaCl2- and α-PbO2-type TiO2 crystals with various Al3+ concentrations using a multi-anvil press. Al3+ is incorporated into the CaCl2- and rutile-type phases mainly in the form of 3Ti4+ = 4Al3+, while the coupled substitution of Ti4+ = Al3+ + H+ is dominant in the α-PbO2-type structure, forming Ti1−x(AlH)xO2 solid solutions. Consequently, the water solubility in Al-bearing α-PbO2-type TiO2 is at least one order of magnitude greater than those in rutile- and CaCl2-type TiO2 phases, making TiO2 a significant water carrier at the pressure-temperature (P-T) conditions in the mantle transition zone (410 to 660 km depth in deep Earth’s interior), when coexisting with Al3+ and Fe3+. High-P and high-T Raman spectra were collected for these synthetic samples. The CaCl2- and α-PbO2-type phases irreversibly transform to a rutile-type structure at 950 K and ambient pressure. A reversible α-PbO2 → baddeleyite phase transition in TiO2 is detected at approximately P = 10 GPa and T = 300 K, and incorporating smaller amounts of Al3+ cations increases the phase transition pressure. The lattice vibrational modes typically shift to lower frequencies at elevated temperature and higher frequencies with increasing pressure due to variations in Ti(Al)-O bond length with temperature or pressure. Fourier transform infrared (FTIR) spectroscopic measurements were conducted on the samples under high-T or high-P conditions. Both T- and P-dependences are negative for the OH stretching vibrations in these TiO2 polymorphs, except that the OH bands in the α-PbO2-type samples exhibit a blueshift at elevated temperature. A negative linear correlation can be drawn between the measured OH stretching frequencies and the incorporated M3+O6 quadratic elongation, which were computed based on first-principles calculations. The local octahedral distortion can provide useful insights for understanding the M3+ and H+ incorporation mechanisms in TiO2 and SiO2 structures.

Synthesis of Polyether Ester Plasticizer and Its Application Performance in Hydrogenated Nitrile Butadiene Rubber

ABSTRACTFour polyether ester plasticizers containing both ester groups and ether bonds were synthesized using 1,4‐butanediol, adipic acid, and alkyl ether alcohols as raw materials. By varying the type of end‐capping alcohol ether, the following plasticizers were prepared: poly (butylene adipate dibutyl ether) (PBADBE), poly (butylene adipate butyl ether) (PBABE), poly (butylene adipate dimethyl ether) (PBADME), and poly (butylene adipate methyl ether) (PBAME). These plasticizers were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance spectroscopy (1H‐NMR), and thermogravimetric (TG) analysis. Furthermore, their differences in cold resistance, heat resistance, and physical‐mechanical properties in hydrogenated nitrile‐butadiene rubber (HNBR) were investigated. The results showed that among the rubber compounds containing the four polyether‐ester plasticizers, the compound with PBADME demonstrated superior heat resistance and low‐temperature performance. Specifically, the PBADME‐containing compound exhibited a TR10 temperature of −39.9°C and a brittleness temperature of −54°C. This significantly broadened the operating temperature range of the plasticizer, making it suitable for applications requiring both high‐temperature and low‐temperature performance.

Doxycycline-integrated silk fibroin hydrogel: preparation, characterizations, and antimicrobial assessment for biomedical applications

BackgroundTooth extraction, a common dental procedure, is often accompanied by pain, trismus, and swelling due to alveolitis caused by oral bacteria. Doxycycline is prescribed to alleviate infection and improve socket healing, but its immediate absorption in the bloodstream makes the treatment less effective at oral sites. This emphasizes the importance of a drug delivery system to gradually slow its release at the oral wound site and increase its bioavailability to make the treatment effective over time.MethodsSilk fibroin (SF) - doxycycline hyclate (DH) hydrogel was developed and subsequently characterized for gelation kinetics, swelling, stress-strain analysis, morphology using scanning electron microscopy, interaction between SF and DH using Fourier transform infrared (FT-IR) spectroscopy, drug release profile, antibacterial efficacy, and biocompatibility studies.ResultsThe results indicated that the SF-DH hydrogel maintained its structural integrity, tolerated stress and strain, and featured interconnected pores, confirming DH integration within the SF matrix. The SF-DH hydrogel formed within 8 h with the pore size range of 20–150 μm and 90.72 kPa Young’s modulus. The drug release profile showed the increased release of DH up to 2 h, followed by sustained release till 8 h. The zone of inhibition was smaller with SF-DH hydrogels compared with DH for both Staphylococcus aureus and Streptococcus mutans. Furthermore, MC3T3-E1 cells showed 90% viability with SF-DH hydrogel.ConclusionsThe findings suggest that SF-DH hydrogel showed sufficient mechanical strength, pore size, antimicrobial activity, and biocompatibility. Further in vivo and clinical tests are required to prove its efficacy in effective socket healing.

Synthesis and Characterization of Sodium Alginate Spheres Functionalized with Dicarboxylic Acids for Copper Removal in Aqueous Media

AbstractNew polymeric spheres of sodium alginate (AlgNa) containing dicarboxylic acids—maleic acid (MA) and oxalic acid (OA)—were developed for adsorption of copper metal from water. Water adsorption capacity, elementary composition, structural, morphological, vibrational, and thermal properties were characterized by scanning electron microscopy (SEM), intumescence degree (IG), X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR) spectroscopy, and differential scanning calorimetry. SEM data revealed that functionalization with dicarboxylic acids affects the morphology and surface of the AlgNa matrix. Sample containing MA (0.35 ± 0.004 g) absorbs more water than the OA sphere (0.28 ± 0.007 g). XRD patterns showed that the AlgNa–MA and AlgNa samples exhibit an amorphous nature, whereas the AlgNa–OA sample has a partially crystalline phase. Adsorption experiments were conducted to analyze whether the synthesized spheres could be optimized to reach the best performance in copper adsorption. The adsorbents were most efficient at the highest dosage used (250 mg), corresponding to removal percentages of 84.54 ± 3.97% (AlgNa), 94.21 ± 3.04% (AlgNa–MA), and 84.22 ± 3.39% (AlgNa–OA). The energy‐dispersive X‐ray spectroscopy maps validated the incorporation of Cu2+ ions on the surface of the adsorbents. Kinetic and isotherm assays confirmed the highest efficiency of AlgNa–MA spheres.

Synthesis of photo-responsive κ-carrageenan-based hydrogels for drug delivery application.

Natural polymer-based hydrogels may act as versatile platforms in controlled drug delivery. In this regard, photoactive κ-carrageenan (κ-Crg) hydrogels modified with cinnamate (CN) groups are developed for pH-sensitive release of drugs. κ-Crg-CN derivatives containing 17%, 33%, and 49% cinnamate contents, named κ-Crg-CN1, κ-Crg-CN2, and κ-Crg-CN3, respectively, are prepared and cross-linked by UV-induced [2π+2π] cycloaddition. Fourier transform infrared (FTIR) spectroscopy, Nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and elemental analysis are conducted for structural characterization. Rheological measurements showed an increased degree of cross-linking density with the increase in cinnamate content, as represented by storage modulus (G') values of 226Pa for κ-Crg-CN1, 631Pa for κ-Crg-CN2, and 967Pa for κ-Crg-CN3. Also, drug encapsulation efficiency using theophylline was significantly improved: 48% for κ-Crg-CN1, 63% for κ-Crg-CN2, and 85% for κ-Crg-CN3. Theophylline release studies showed that at pH1.2, it was slower than pH7.2, with a release rate inversely proportional to the cinnamate content. Kinetic modeling showed a non-Fickian transport mechanism that involved diffusion and polymer relaxation. These results show that κ-Crg-CN hydrogels can act as tunable, pH-sensitive drug delivery systems, with mechanical properties and release profiles precisely tailored by cinnamate functionalization for applications in controlled drug delivery.

Insights into the expeditious photocatalytic performance of greenly fabricated CeVO4 nanoparticles using Polyalthia longifolia leaf extract

Insights into the expeditious photocatalytic performance of greenly fabricated CeVO4 nanoparticles using Polyalthia longifolia leaf extract

Co3O4 derived ZnO: An effective electrocatalyst for oxygen evolution reaction in alkaline media

Co3O4 derived ZnO: An effective electrocatalyst for oxygen evolution reaction in alkaline media

Effects of dimethylarsenate coprecipitation with ferrihydrite on Fe(II)-induced mineral transformation and the release of dimethylarsenate.

Organoarsenicals are toxic pollutants of global concern, and their environmental geochemical behavior might be greatly controlled by iron (Fe) (hydr)oxides through coprecipitation, which is rarely investigated. Here, the effects of the incorporation of dimethylarsenate (DMAs(V)), a typical organoarsenical, into the ferrihydrite (Fh) structure on the mineral physicochemical properties and Fe(II)-induced phase transformation of DMAs(V)-Fh coprecipitates with As/Fe molar ratios up to 0.0876±0.0036 under anoxic conditions and the accompanying DMAs(V) release were investigated. The presence of DMAs(V) during Fh formation gradually decreases the mineral crystallinity. With increasing DMAs(V) content, the specific surface areas of the coprecipitates are decreased owing to particle aggregation, while the micropore sizes are negligible changed. Fourier transformed infrared (FTIR) and As K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy show that, part of DMAs(V) binds to Fh surfaces in the coprecipitates by forming bidentate binuclear inner-sphere complexes through As-O-Fe bonds. During the reaction of the coprecipitate with 1mM Fe(II) for 336h, DMAs(V) inhibits the Fh transformation to goethite. No goethite forms at pH 4; at pH 7 low content of DMAs(V) hinders the further conversion of lepidocrocite to goethite, while high content of DMAs(V) completely inhibits goethite formation. DMAs(V) in the coprecipitate is continuously released into the solution, with the released proportion being generally increased with the increase of DMAs(V) content, pH and Fe(II) addition, probably owing to the desorption of weak inner- and outer-sphere DMAs(V) complexes bound on the Fh surfaces upon the Fh aging and transformation to lepidocrocite and goethite. These results provide deep insights into the fate and mobility of organoarsenical pollutants mediated by Fe (hydr)oxides in natural environments, and help design effective and ecofriendly remediation strategies for As polluted soils and sediments.

Evaluating the combined effect of photooxidation and thermal ageing of bitumen

Up to date, mainly temperature or UV light is incorporated into laboratory bitumen ageing procedures. However, the impact of visible light showed some interesting results recently. Therefore, an unmodified binder was exposed to a combination of temperature and different sun and narrow UV and blue light lamps. The aged binders were analysed with Fourier Transform Infrared (FTIR) spectroscopy, dynamic shear rheometer (DSR) and SARA fractionation. The results showed synergistic effects between temperature and light. Surprisingly, different lamp intensities lead to almost the same level of ageing, indicating that merely a certain amount of photoenergy is needed. Lastly, comparing the UV and blue light domain to sunlight showed that while exposed to the same amount of photoenergy, its effect on rheology differs, where sunlight showed the most impact on ageing. This highlights the importance of sunlight to the ageing process to sufficiently understand its combination with other ageing inducing factors.

Degradation of polyester coil-coated materials by accelerated weathering investigated by FTIR-ATR chemical imaging and impedance analysis

Degradation of polyester coil-coated materials by accelerated weathering investigated by FTIR-ATR chemical imaging and impedance analysis

Spectroscopic studies of conformational polymorphism in 4-methylphenol

In this work, conformational polymorphism in 4-methylphenol has been studied using a Fourier-transform infrared (FTIR) spectroscopy. The first time we have received the FTIR spectra of the stable and two metastable phases of 4-methylphenol and their temperature dependencies at temperatures from 300 to 12 K in the spectral region of the methyl group (CH3) deformation vibrations. Analysis of the FTIR spectra showed that there are significant differences in the position and shape of the bands related to the deformation bending β(CH3) and rocking ω(CH3) vibrations when passing from one polymorph to another. A particular feature of the methyl group in the 4-methylphenol molecule is that it does not take part in hydrogen bonding interaction. This made it possible to relate the observed changes in the FTIR spectra with changes in the geometrical parameters of the 4-methylphenol molecule. This in turn allowed us to conclude that the polymorphs under study consist of different conformers of 4-methylphenol molecule.

Evaluation of the structural and physical properties of CdxZn1-xS nanocomposites depending technological condition

The study presents nanocomposite materials based on CdxZn1-xS, synthesized as thin films and nanoparticles through two distinct techniques—sonochemical and SILAR synthesis techniques. The characteristics of these materials were investigated using X-ray diffraction (XRD), Ultraviolet spectroscopy (UV-Vis), Fourier-transform infrared (FTIR) spectroscopy, and Scanning Electron Microscopy (SEM). In the sonochemical approach, samples were prepared with three different stabilizers for comparative analysis to determine influence of type of the stabilizers. Meanwhile, the SILAR approach created thin layers with different components (distinctive x value-CdxZn1-xS) at various grown temperatures utilizing polyvinyl alcohol (PVA) as a substrate. At the same time, nanocomposite materials compared of same x value for CdxZn1-xS composite materials by sonochemical and SILAR synthesis technique depending on technological condition.

Identification and characterisation of the recently detected cathinone N-cyclohexyl pentylone.

Synthetic cathinones are one of the most consumed new psychoactive substances (NPS) in New Zealand and around the world. The combination of the ease of manufacture and simple modification of the chemical structure of cathinone lends this class of stimulants as one that is difficult to predict and legislate. A major challenge in the rapid identification of NPS is access to valid spectra and reference material and with the constantly changing landscape of these "designer drugs", these are difficult to obtain. This paper reports a new synthetic cathinone, N-cyclohexyl pentylone, which was detected within in a sample received from Drug Checking Service Provider, New Zealand Drug Foundation (NZDF). Structural elucidation and characterisation were carried out using gas chromatography - mass spectrometry (GC-MS), Fourier-transform infrared (FTIR) spectroscopy, high-resolution mass spectrometry (HRMS), and nuclear magnetic resonance (NMR).

Biodegradable Plastics from Marine Biomass: A Solution to Marine Plastic Pollution

Biodegradable Plastics from Marine Biomass: A Solution to Marine Plastic Pollution